Open-​​pit coalminers face a unique set of occu­pa­tional haz­ards. The dozers, dump trucks, and shovels they operate stand five or six sto­ries tall and often sport tires two or three times their height.

Yes, the equip­ment allows the miners to move hun­dreds of tons of mate­rial at a time from the com­fort of their osten­sibly safe seats inside the cab. But the effect of the whole-​​body vibra­tion caused by oper­ating heavy-​​duty vehi­cles has not been thor­oughly studied, said Jack Den­ner­lein, a pro­fessor in the Depart­ment of Phys­ical Therapy with an engi­neering background.

Sig­nif­i­cant data has already shown that people who sit in a vibrating envi­ron­ment for long periods of time are at higher risk for low back pain, which accounts for one of the largest dis­ability claims in the United States. Under­standing the mech­a­nisms of the injury, and how to pre­vent it, Den­ner­lein said, is a crit­ical public health concern.

What we’re doing is taking that knowl­edge and applying it to open pit mines, which have a very dif­ferent type of whole body expo­sure,” Den­ner­lein explained. “Miners are dri­ving over roads that have just been made, they’re get­ting dumped on, so the whole truck shakes, they’re get­ting shock impulses—a whole dif­ferent kind of vibra­tion that people haven’t studied before.”

Backed by funding from the Alpha Foun­da­tion, a non­profit that sup­ports research to pro­mote the health, well­ness, and safety of miners, Den­ner­lein is hoping to change that. He and his team will add vibra­tion sen­sors to the floors and seats of these heavy-​​duty vehi­cles to see how dif­ferent seats respond to the stimuli.

Open pit coal miners expe­ri­ence a unique ver­sion of whole body vibra­tion using extremely large equip­ment. Photo via Thinkstock.

Den­ner­lein will be looking at both active vibra­tion can­celling sys­tems and pas­sive seat sus­pen­sions, with the hope of iden­ti­fying one that is most suc­cessful at lim­iting whole body expo­sure, and thereby reducing low back pain.

In a pilot study, Den­ner­lein looked at the average overall vibra­tion reaching the oper­ator using stan­dard tech­niques applied to dri­vers and pilots. This data strongly sug­gested what he expected—more expo­sure to vibra­tion causes more injury. “But we really want to look at the peak, acute expo­sures,” said Den­ner­lein, noting that the miner is more prone to expe­ri­ence shock impulses than someone dri­ving on the freeway for a few hours.

With data from his forth­coming study, in addi­tion to the dri­ving and health records of the miners, Den­ner­lein hopes to build a model that could pre­dict future health out­comes based on their expo­sure to whole-​​body vibration.